Should you have to pay to drive in downtown Seattle?

When the Highway 99 tunnel through Seattle opens to traffic in 2019, state transportation officials plan to charge a toll to drive through it.

That has prompted another idea to gain steam: a toll on downtown surface streets.

The Highway 99 tolls have yet to be determined by the Washington State Transportation Commission. But the Washington State Department of Transportation has commissioned studies of different ranges, including tolls between $1.00 to $5.00. WSDOT’s latest estimate is that tolls ranging between $1.00 to $2.50 could raise enough money to meet requirements set out by state law.

Seattle City Councilmember Mike O'Brien is concerned people will detour through downtown streets in order to skip the Highway 99 toll. He spoke about it in an October City Council committee meeting.

O'Brien: "If they toll at the rate necessary to pay back the bonds, we expect significant diversion to our city streets, which could have a serious impact on traffic downtown and specifically on transit times downtown."

He's proposing that the city pay for a $200,000 study on the topic. O'Brien wants to know whether tolling the highway and nearby Seattle streets would keep traffic balanced.

The Washington State Transportation Center at University of Washington is already studying the topic. Director Mark Hallenbeck said tolls tend to change driver behavior.

He said people willingly take congested streets just to avoid a road with a fee, but warns that kind of diversion behavior won’t work downtown.

Hallenbeck: "The surface streets can't handle considerably more traffic, downtown Seattle will end up in gridlock."

Hallenbeck said if drivers avoid the tunnel, it will also hurt the state. WSDOT needs to collect toll money on Highway 99 to pay back tunnel construction costs.

He thinks congestion pricing on streets near the tunnel is the best solution.

Hallenbeck: "If you're going to duck the tunnel, not only are you going to get stuck in congestion in downtown Seattle, but you're not going to save any money."

Hallenbeck recommends a toll on drivers who spend less than two hours downtown.

Before the city considers the idea, O’Brien wants to know who would be impacted.

O'Brien: "Who is actually driving to and from downtown, at what times, what the demographics of those folks are, economic background and things like that."

Money for a consultant study could be included in the 2018 city budget, if approved by the City Council.

11/02/2017: This post has been updated to reflect the latest studies on possible toll rates.